The California Public Utilities Commission (CPUC) has approved San Diego Gas & Electric’s (SDG&E) proposal to accelerate construction of a key transmission line to try to put it in service by September 2005--or sooner, if possible--to help avert potential electricity supply shortages and reduce energy costs for consumers.

In July 2004, the CPUC approved construction of the new 230,000-V (230 kV) electric transmission line along SDG&E’s existing right-of-way from its Miguel substation in the southeast region of San Diego County to its Mission substation in Mission Valley. The original in-service date for the line was June 2006, but SDG&E filed a “petition for modification” with the CPUC in September 2004 to obtain regulatory approval of minor technical changes in the project that would allow the utility to operate portions of the upgraded facilities as early as September 2005. This month, the CPUC granted SDG&E’s request.

“We are pleased the commission has recognized the importance of moving ahead as quickly as possible on vital infrastructure improvements that will enhance overall reliability of the system and provide immediate cost savings to customers,” said David L. Geier, vice president of electric distribution & transmission for SDG&E.

“The line also will ease congestion on the power system and, as a result, reduce overall energy costs for consumers throughout Southern California. Getting the line in sooner will mean an estimated cost savings of US$8 million to $13 million for customers.”

State officials are increasingly concerned about whether electricity supplies will be adequate next summer and fall, especially if there is a heat wave. The California Energy Commission now estimates the Southern California region will need another 1700 MW to meet reserve margins next September, if hot weather drives up demand.

“By easing the transmission bottleneck in Southern California, this line improves access to electricity outside the area,” said Geier. “It will help California utilities bring in as much as 500 megawatts from other sources--such as power plants in Arizona and along the U.S.-Mexico border--to meet the power shortfall.”

Construction of the Miguel-Mission line is a vital piece of SDG&E’s ongoing transmission strategy to improve the overall reliability and flexibility of the region’s electrical system, Geier said.

Earlier this month, Governor Schwarzenegger held a news conference in Folsom, California, to celebrate the completion of another transmission project in Northern California that also will help improve the flow of electricity throughout the state and help avert outages related to power gridlock.

“To use the familiar analogy, the recent addition of new equipment at our Miguel substation was like adding lanes to the freeway system,” said Geier. “Once this line is built, it will act as an ‘off-ramp’ to funnel the electricity around what had been a transmission log jam, allowing more power to flow through the upgraded Miguel intersection. We cannot realize the full benefit of the substation improvements until the line is in service.”